A book based on a radio series that inspired a devoted worldwide following; sold over 14 million copies; spawned comic books, stage adaptations, a TV series, a movie, four more books, yet more radio serials; and was voted number 4 in the BBC's poll of the top 100 books of all time.

Not at all. Hitchhiker's only uses sci-fi tropes and themes as a vehicle for comedy, using the limitless possibilities of science fiction to poke fun at earthly concerns such as religion, scientists, politicians, estate-agents and people from Islington.

There had been comedy sci-fi before and has been since, but nothing like this. The success of Hitchhiker's is due to the singular voice of Douglas Adams, which gives the book its unique, extremely funny and quintessentially English humour.

A key part of Adam’s comic technique is bathetic contrasts of scale. This can mean mixing the small and mundane with the vast and distant, as in the opening of the book. A mediocre man in a nondescript part of England whose dreary cottage is about to be demolished to make way for a local bypass is juxtaposed with the vast Vogon constructor fleet about to demolish the entire planet Earth to make way for a hyperspatial express route.

Adams doesn't only play with contrasts of physical scale: he also brilliantly juxtaposes the trivial and parochial with the vast and mythic. His universe is filled with bizarre creatures and startling technology but, however outlandish the aliens and exotic the robots may be, they are all essentially as petty and self-absorbed as the earthlings: dull bureaucrats, or paranoid depressives.

Adams delights in word play and has a sense of the absurd that has led critics to draw parallels to the work of Lewis Carroll, although his comic voice might more fairly be compared to P. G. Wodehouse. Adams makes his universe utterly his own, not least through his astonishing gift for memorable character names which manage to sound both authentic and grotesquely absurd: Prostetnic Vogon Jeltz, Slartibartfast, Zaphod Beeblebrox and, best of all, the “nicely inconspicuous” Ford Prefect.

The book has a narrative that whips along, anarchic frenzied humour, and loveably-deranged characters, but that doesn’t mean it lacks depth. Many of the quotations from the Guide or Encyclopaedia Galactica deal with themes of atheism versus religious dogma and, in a mocking and yet still profound way, with the meaning of life, the universe and everything.

The Hitchhiker's Guide to the Galaxy is a true book of its era. Coming at the end of the 1970s, when cynicism about the lost hippy ideal had set in, Hitchhiker's identified with that same ex-hippy generation that was now starting to set the social and political agenda. Ford Prefect, a Rolling Stone journalist manqué, and Zaphod Beeblebrox, a bombastic rock star in everything but profession, were the perfect heroes for a generation raised on rock and roll. (It was part of Adams’ comic genius that these two exotic characters would be forced into company with Arthur Dent, possibly the most prosaic hero in all literature).

At a time when people looked to computer technology to shape the future, Adams filled his book with robots, spaceships and super computers – but irritating computers, depressed robots and ships that still ran ticker tape readouts. The strongly atheist message was also well-timed to capitalise on the younger generation’s weariness with the pomposity of the older generation's religion and politics.

Many great books have been adapted successfully for other media, but I can't think of such a brilliant novel ever being adapted from a drama. The book does end rather arbitrarily, based as it was on radio scripts that were cobbled together under difficult circumstances. The ending is an obvious set up for a sequel rather than a satisfying denouement, but then if this encourages you to read the other books in the series that is no bad thing.